For example when I'm writing a math paper, I want to offer the proof as clear as I can, since I can't guarantee the education backgroud of my readers are at the same level. But that would be too much details, and would cause a lot of scroll down for certain readers.
So the question naturally arise, is there a math editor, using latex, contains this function? I know this probably can't be done in PDF format, but are there any other format and math editor supporting this "Expand and Collapse"/"Fold and Unfold" function?
P.S. I believe this should be a natrual question for Mathematicians and should be already solved somehow somewhere.